The present disclosure relates to an apparatus for cleaning a leading edge of a rotor blade of a wind turbine. Further it relates to a rotor blade of a wind turbine comprising an apparatus for cleaning a leading edge of the rotor blade
Modern wind turbines operate rotor blades at tip speeds of up to 80 m/s (i.e. more than 150 mph or more than 250 km/h). During operation, dirt accumulates on a blade surface mainly at and close to a leading edge of the rotor blade. The accumulation of dirt on the blade surface results in increased surface roughness which changes the aerodynamical characteristics of the blade. On one hand, a maximum lift of the rotor blades decreases which leads to lower performance of the wind turbine. For example, the maximum power level for stall controlled turbines may, drop as much as 45%. Hence, power production is decreased.
Further, an angle of attack at maximum lift decreases due to dirt accumulation on the blade surface, which results in a larger probability of stalling the blade. The angle of attack is the angle between an airfoil chord and a free-stream velocity of the airflow. For a pitch controlled turbine, blade stall not only decreases energy capture but also leads to an unnormal operation condition that potentially endangers the turbine safety at the moment of flow re-attachment.
Additionally, flying bugs that collide with the rotor blade may cause blade fouling. The bug bloom is affected by several parameters such as temperature, humidity and also wind speed. Typically, bugs can only fly up to wind turbine rotor height during low wind speeds (e.g. less than 10 m/s).